Oakland A's rotation by the numbers: Chris Bassitt is taking off

The Oakland A's haven't been a good team in 2015, but their rotation is still so bright that it's blinding. A's starters have a 3.05 ERA in 113 games, which is by far the best in the American League -- next-best is Tampa Bay at 3.48. Granted, part of that success came from the now-departed Scott Kazmir, but he was only 20% of this unit. There is still an awful lot to like here.

Here's a key stat for each member of Oakland's starting rotation.

Sonny Gray | 1st

That's his AL rank in ERA; he leads the league with a 2.06 mark. He's thrown complete games in three of his last six outings, two of them shutouts, and he's got a 1.72 ERA in that span. If anyone is as hot as Kazmir is right now for the Astros, it's Sonny. He is currently a front-runner for the AL Cy Young.

Jesse Chavez | 5.79

That's his ERA in his last nine starts. Entering June 23, he had a 2.52 ERA, a 3.68 strikeout-to-walk ratio, and he'd allowed four homers in 78⅔ innings. Since then, he's struggled quite a bit, with a 1.89 K:BB and eight homers in 46⅔ innings. Five of those nine starts included at least four earned runs, and only three times did he complete six innings. It hasn't all been bad -- he mixed in six sparkling shutout innings against the Twins, and his last time out he went seven strong against the Astros. He's hit a bit of a wall, but just like the youngsters around him, the rest of this lost year is an opportunity for him to experience a (mostly) full season of starting and establish a new career-high in innings (current high: 146).

Chris Bassitt | 5.14

That's his strikeout-to-walk ratio in seven starts this season, 36 Ks and 7 BB. That ratio comes attached to a 2.27 ERA, as well. Bassitt isn't just surviving in the rotation, he's thriving, and despite every available scouting report he is actually holding left-handed hitters to a lower OPS than righties (though his K:BB is significantly better against righties). He's pitched into the seventh inning in each of his last three starts, and in each one his strikeouts have risen while his hits allowed have gone down; in his last outing he fanned 10 batters and flashed a filthy curveball. He's getting better and better each time out, which gives me hope that he could stick in the rotation after all. In 12 career starts (dating back to last year with the White Sox), he has a 2.86 ERA with 55 strikeouts and 19 walks. The Hound might be here to stay.

Kendall Graveman | 0

That's how many times he's completed seven innings in his last five starts, after doing so in six straight outings in June and early July. He has a 6.20 ERA in that span, with two starts that were utter disasters. He still looks better than he did in April, when he was completely over-matched, but this is a reminder that rookie pitchers will go through ups and downs. All told he has an ERA+ of exactly 100 for the season, and he's shown us what he can do when he's on his game. His next job is to get himself back on track once more before the end of the season so he can finish the year on a high note. One other number that I almost picked for Graveman: his 49.5% groundball rate (164 grounders on 331 batted balls, according to Fangraphs), which is only 31st out of 99 MLB starters with at least 100 innings. I don't know, I just thought it would be higher, and maybe it will rise as he gains more experience in the league and figures out how to get hitters to roll over on his pitchers like he wants them to.

Aaron Brooks | 0.6

That's his bWAR after just two starts, or 0.4 if you prefer fWAR. That is a "fun with small samples" stat, of course, because he's pitched two amazing games so far but hasn't had more time to balance them out with the stinkers that eventually come for every pitcher. For now it extrapolates to a 9.6-bWAR season! But the point is that Brooks, who looked like he might eventually settle in as a reliever when Oakland acquired him, has exceeded all possible expectations in his first two outings and given us all hope that he might turn out to be more than initially expected. What's more, he's looked good doing it rather than completely fluking into early success. He's not going to keep throwing seven-inning gems every time out, and a trip to Toronto's homer-friendly Rogers Centre to face the Blue Jays' terrifying lineup will be a real test for the right-hander. But darn if that 12:1 strikeout-to-walk ratio doesn't grab my attention. Brooks will probably have the rest of the year to prove he belongs in the 2016 rotation, and based on what we've seen so far I can't immediately tell you that he won't do just that (though with an ERA far north of his current 1.26). As Nico said in his Eyeball Scout report, "You intrigue me, Aaron Brooks."